Research

Buma et al., Policy solutions to better assess progress toward Paris goals given warming-induced ecosystem emissions, which shorten timelines by 2–5 years, One Earth (2025), https://doi.org/10.1016/j.oneear.2025.101571

Faculty Authors

John Holdren Photo

John Holdren

Teresa and John Heinz Research Professor of Environmental Policy

What are the Paris Agreement goals?

In 2015, nearly 200 nations adopted the Paris Agreement at the United Nations Climate Change Conference in Paris France (the United States recently withdrew from the agreement). The participating nations pledge to try and keep the global temperature from rising 1.5 or 2 degrees Celsius above pre-industrial levels—or at least stave the increase off for as long as possible. 

How much closer is the world to missing its climate goals?

According to new research from HKS Professor John Holdren and others in One Earth, we’re 25% closer to breaching the goals than we thought. Prior estimates that we’d cross the 1.5 threshold by 2032 and the 2 degree rise by 2051 built in more time than we actually have. Holdren and his coauthors suggest we’ll instead pass a 1.5 degree rise by 2030 and a 2 degree increase by 2046. There are two main reasons for this:

  • Existing measurements are based on “direct” impact to climate, such as when a nation burns fossil fuels. But these calculations miss “indirect impacts” that follow human-led impact, such as the melting of permafrost, warming wetlands, or the loss of forests to wildfire.
  • Existing measurements track the emissions of each government’s “managed land,” which leaves the emissions of remote forests, wilderness, or significant portions of the Arctic uncounted.

What can nations do to address indirect emissions?

The authors suggest a number of paths for addressing the challenge of indirect emissions, including:

  • Tracking them: Measuring emissions is key to addressing emissions. The authors suggest that international reporting standards begin tracking indirect emissions, not just direct ones. They also suggest that nations could voluntarily track these emissions even before formal standards shift.
  • Using them to adjust predictions: The authors emphasize that climate modeling, which is used to predict impacts of climate change, take these indirect emissions into account.
  • Mitigating their impact: The authors suggest that nations take steps to manage indirect emissions, such as preventing wildfires or managing water levels in wetlands. They suggest that nations with heavier emissions hold a greater responsibility for such mitigation. 

 

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